How often can you machine polish a car?

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cheekyage

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Hi all,

I'm trying to understand how many times you can machine polish a car.

By reading all the how-to threads it seems that every time you machine polish you are effectively removing the clear coat.

This would then limit the amount of "play" you have for correction.

As I am new to this, I've put together a few newbie questions:

1. How would I know how much "play" there is to ensure a safe correction?

2. How often would you machine polish a car?

3. If you machine polish in January 2014 and then go at it again in February 2015 wouldn't I be removing more clear coat and putting myself at risk of causing paint damage?

4. If you are fixing another Detailers mistake or poor correction in the space of a few days/weeks/months - would this be removing more clear coat?

Appreciate your help and advice :)
 
1. This is why a paint depth gauge is essential. One time you could remove "x" amount of microns of clearcoat and more or less the next time and soo on....Also will depend on the make of car for example a VAG car will be about 140 microns (average) whilst a Mitsubishi Evo could be about 100 microns (or less). Also you do not know the history of the paint. It could have been repainted, so the strike through point changes.

2. You would want to work on the basis of removing as little clear coat as possible. How often can you ? that again depends on question 1.

3. Everytime you are correcting you are removing some clearcoat

4. Depending on the other detailers mistake or poor correction, if its only hologramming, should be an easy fix to refine. If its been striked through, its game over and if its anything else, let us know.

I think the main things im trying to say.....without a paint depth gauge, its like playing russian roulette.
 
This is a great question that I was always curious about. The manager of a highly respected auto body shop in my area told me they never recommend machine polishing JUST to make paint perfect and remove
swirls because you are always removing small amounts of clearcoat and
even paint. He said why would you do that, you are just shortening the life of your car's paint.
 
1) That's something that no one really knows. Having more paint is always better. A PTG will tell you the total thickness of all the layers, but no one knows how thick the clearcoat actually is.

2) A light polish with a finishing polish every year or two is probably OK, but I would not compound a car more than a few times. I think Ford and GM set maximum material removal limits, and that information is out there somewhere.

3) Yes.

4) YMMV.
 
I could go on, and on about the benefits of EPTG's...for pages upon pages...
But it really depends on the type of correction that's needed, IMHO.

What if it was proven that the vehicle's BC/CC paint system measured at a total film-build of 125 microns---with the CC being 55 microns <<<(thick!)---but the scratch/defect is between 56 and 126 microns:
Are you going to go chasing that scratch/defect!

Now:
If you want to use a machine polisher (instead of by hand),
but worry about this "how many times issue":
Use the polisher with glazes. Perhaps with very fine polishes only.

Your vehicle will look as though it has a decent finish...
Without it ever actually have incurred any "cutting".

Bob
 
quit shilly-shallying folks. What is the answer? Start from new, say a GM car, Fine polish, say Megs 205. Sure he can buy a thickness gauge, but how many times can he expect to have at it? 5? 20?

If its 20, I'd say, sure, do it every couple of years if you want. If its 5, I'd say ration your polishing to when you really really need it.
 
peter hurcos said:
quit shilly-shallying folks. What is the answer? Start from new, say a GM car, Fine polish, say Megs 205. Sure he can buy a thickness gauge, but how many times can he expect to have at it? 5? 20?

If its 20, I'd say, sure, do it every couple of years if you want. If its 5, I'd say ration your polishing to when you really really need it.
Click to expand...
OK...M205.

-What are the expectations/trying to accomplish
-What is the paint-system (SS; BC/CC)
-What "type" of pads.
-Which polisher
-How much downward pressure
-Arm speed
-Heat generation
-NO. of total "passes" at each polishing-session
-How much CC is removed at each polishing-session (EPTG)
-etc., etc.

I could guesstimate...
But given the above variables: To what avail?

The less the top-coat paint-film is abraded/touched...
The better the chances will be that this paint's expected service life will be within reach.


Bob
 
I'd say using 205 on a normal polishing pad he shouldn't ever have to worry about going through in the normal Lifetime of clear.. say 10 years give or take. Probably twice a year, sound about right.
 
nodule said:
This is a great question that I was always curious about. The manager of a highly respected auto body shop in my area told me they never recommend machine polishing JUST to make paint perfect and remove
swirls because you are always removing small amounts of clearcoat and
even paint. He said why would you do that, you are just shortening the life of your car's paint.
Click to expand...

Yes, but body shops use rotary buffers. I've yet to go into one that uses a (lowly) DA such as the PC, GG, Rupes, or even a FLEX 3401 (forced rotation). I had one send me a Jag a few weeks back and when I told the shop manager I was going to go over the entire car with a "DA" he said, "You're going to sand it?" He had never heard of anyone using a DA type machine to correct paint!

That's not anything bad towards the shops, just that they are in a different environment. They come from a world where there are huge time constraints and need to make things happen asap. Where we think nothing of spending 10, 12, 20, even 30 hours polishing paint to the n'th degree they'll whip over it with a rotary for a couple of hours and call it a day.;) Yet I get work from shops BECAUSE we use the machines we use. :D

When we delivered the Jag back to the shop, complete with a "coating" they were blown away. Not only did they not know about a DA polishing paint, they also had originally called us BECAUSE we did "coatings", and the insurance company was paying for a new coating on the customers car. When we told them we put about 16 man hours into the job they couldn't believe it. (Because they put about 3 and that's ALL they'll do.) Actually we ended up with 4.5 extra hours BECAUSE they didn't cut and buff the right side, (as we had instructed). It took that extra time to bring that side up to the same level as the rest of the car that had either been repainted, or color blended. To them however they were not going to touch the right side, BECAUSE it wasn't part of THEIR repair. To us though we HAD to, in order to coat the entire vehicle. :rolleyes:



Back to the topic of how many times you could possibly "polish" a vehicle.

That's like saying how many times can I tie my shoes?

How hard to you pull your laces? What kind of work do you do? Are you wearing work boots or running shoes? Do you crawl around on your knees? Or run around in gravel and mud? Or do you walk on carpet all day? Maybe you wear knee pads, but crawl on pavement?

Easy to figure out that your laces (and maybe the entire top of your shoes) may not last 2 months on running shoes if you're crawling around on pavement all day. But if you're working as a cashier they can last for a couple of years.

Same thing with polishing paint. The act of heavy compounding versus the act of light polishing are worlds apart. It's safe to assume that if you never swirl the paint badly, and only lightly polish it, you will probably wear the car out before you wear the paint out. OTOH, get one that's as thrashed out as the new Camry we had last weekend and you're going to get maybe 2 chances TOPS at fixing something that bad. :dunno:
 
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